i"(ni!-ii()KNi:i) ciiTrrs. 



r 



in the other s])ecies of the genus. Besides the supei'ior 

 ,111(1 inferior sii])|)ortiiig- rnys, this tin eoutiiiiis 11 other 

 r;i\s. The 8 or '.) middle ones, in old speeiinens at 

 least, are generally ])ranclie(l, though one may sometimes 

 tind specimens from 130 to 140 mm. in length without 

 a single hranehed ray in the caudal tin. In tiic male 

 all the simple rays of this tin are generally rough 

 througliout their length, hut the hranehed ravs, on the 

 other hand, only from the beginning of the division to 

 the tip: in the female oid\- the uppermost rav is rough. 

 When the caudal lin is folded up, the outer ra\s ai'c 

 generally those which extend farthest baek. 



On the effects of difference of sex on the external 

 parts of the l)ody we tind no remarks in any author 

 before ICksthOm, although they are very striking. In 

 the males tlu; ])ody is generally more cylindrical, and the 

 begiiuiing of the anal tin usually in front of the middle 

 of the l)ody. In these respects, as in several others, the 

 males have retained their position in the juvenile stages 

 of development, which they thus hold in common with 

 the \'ounger females; while we tind that in very old 

 males the anal fin sometimes begins a little behind the 

 middle of the body, thouafh not so far l)ack as in fe- 

 males of equal size. The males generally have also 



higher anal and dorsal fins and longer pectoral and 

 ventral tins, 'fhis prevails in some cases, perhaps in 

 most, to such an extent that the rays of the second 

 dorsal fin, when depressed, extend beyond the base of 

 tiic caudal lin; and it is a nde, to which we have found 

 few exceptions, that in the males the length of the vent- 

 ral tins is greatei' than that oi' the lower jaw. There is 

 also a ditterence according to sex in the relations of the 

 dorsal fins to each other. In the males the base of the 

 second dorsal fin is generally longer than in the females. 

 but the distance between the beginnings of the two fins 

 is less. Though these two ditt'erences ai-e not invariable, 

 the rule holds good if the\- are combined, — -attention 

 being j)aid to the significance of the aliove-inentioned 

 changes of growth — that in tlie males the distance 

 from the begiiuiing of the first dorsal fin to that of the 

 second is less than the length of the base of the latter 

 fin, while in the females, except during youth, it is 

 greater. In tlie latter, too, the belly is more pendent, 

 the anal fin begins behind the middle of the ])ody, and 

 the fin-rays are shorter and not so rough. In the 

 following table we give the most important differences 

 depending on age and sex which we have found in 

 eight females and five males: 



Lcnglli of the body in niillimetres 



., ,. .. Iieiid in % of tlie leiiglli of the I)ody 



.. maxillary bones ,, ,, ,, .. .. ,, ., ,, 



,, „ lower jaw ,, ,, ,, ,, ,, ,, „ ,, 



„ ,, „ ventral tins „ „ „ ,, ,, ,, ,, „ 



Least depth of the tail ., „ ,, ,, „ „ „ ,, 



Distanee from the anal tin to the tip of the snout in °i of the length of the body 



Distanee from the beginning of the first dorsal fin to that of the seeond in 

 % of the base of the Litter _ 



Least depth of the tail in % of the length of the longest ray in the anal fin 



„ ,, ,. .. seeond 



dorsal tin 



Length of the ventral fins in fe of the length of the belly from the insertion 

 of these tins to the beginning of the anal fin 



Length of the ventral fins in % of the distance from the beginning of the 

 1st dorsal fin to that of the "ind 



Length of the ventral fins in % of the distance from the anal fin to the tip 

 of the snout 



Longest ray in the Ist dorsal fin in % of the distance from the beginning 

 of the 1st dorsal fin to that of the second 



Longitudinal diameter of the eyes in }i of the length of the head 



Least breadth of the intcrorliital space in f* of the least depth of the tail. 



Sca7iflinavian Fishes. 





9 j 9 I 9 



78 jl37 1 173 

 28.2i 29.0 29.4 



11.1 



15.2 

 11.5 



3.i< 

 46.1 



V 



206 

 29.3 



11.9 



12.4 12.1 

 le.oi 15.0 15.8 



14.0 12.4 10.8 



3.6 



51.5 



106.4 107.4 

 47.6 35.7 



36.6 22.7 



46.4 

 54.S 

 25.0 



52.6 

 69.0 

 28.3 



33.7 i 34.5 

 22.7 17.2 

 66.7, 100.0 



4.0 3.9 

 50.9 52.1 



46.6 

 33.3 



y 



218 

 29.3 



12.4 

 14.8 

 14.4 



4.1 

 .53.2 



110.3 118.5 109.0 110.0 

 42.1 37.5 



274 

 33. 



15.3 

 17.5 



13 



3.6 



55.6 



ao.f 



44.8 41.3 



57.3, 46.4 



i 



24.4 20.7 



41.3 35.4 



23.5 22.8 

 75.7! 87.5 



28.1 

 50.8 

 64.3 

 27.1 

 34.7 



17.8 



100.0 



34.5 



27.0 



46.2 



61.1 



24.2 



40.5 



12.1 



14.5.0 



s: 7^ 



c n 



cy ^ 



cc,2 



162 

 28.4 

 11.7 



15.4 



19.1 



4.3 



47.3 



91.2 



38.8 



19.0 



79.S 



100.0 



40.5 



60.0 

 24.0 

 57.1 



170 

 30.0 



12.7 

 14.9 



17.1 



3.5 



48.0 



94.6 

 27.3 



15.4 



66.0 

 82.8 

 35.6 



w3 



>\ 



18.7 



73.4 

 90.4 

 38.5 



21.8 



65.7 



272 

 30.0 

 15.1 



17.2 



26.1 

 4.0 



51.8 



13.3 



100.0 



54.8 55.7 

 16.6' 15.0 



81.4 131.5 



34.8 50.4 



53.0 



14.7 



81.5 

 14.7 



113.3 133.3 114.31 127.3 



V 



76.0 

 29.8 



11.2 



14.9 



12.3 



3.9 



47.5 



96.5 

 44.9 



34.7 



50.6 



61.J 



25.9 



41.2 

 20.6 



82.4 



23 



I 



201.5| 225.0 



30.1 29.8 



12.8 

 15.8 



13.1 



I 



3.8 



52.7 



13.1 



15.9 



19.« 



3.9 



48.9 



111.0 93.1 



39.3I 29.7 



28.4 17.6 



47.1 76.9 



59.0 



97.2 



24.9 40.0 



37.3 60.9 



18.6 17.0 



lOl.G 109.1 



